1. Field of the Invention
The present invention relates to an accelerometer arrangement and more particularly relates to an accelerometer arrangement for use in a motor vehicle.
2. Background Information
An accelerometer may be used in a motor vehicle to measure the deceleration of the motor vehicle. Such an accelerometer may be utilized to trigger a safety device, such as an inflatable air bag, when the deceleration detected by the accelerometer corresponds to accident conditions.
It is important that an air bag is inflated at the correct instant. The reason for this is that an air bag takes a certain period of time to become fully inflated, but once it has inflated it then starts to deflate. It is therefore important that when a person travelling in a motor vehicle is thrown forwardly, in an accident, the air bag should be fully inflated just before the person is thrown forwardly.
It is found that the deceleration curves for a motor vehicle involved in an accident depend very much upon the relative speed of impact. Of course, the rate of forward travel of a person towards an air bag provided in a vehicle also depends upon the speed of the vehicle before the initial impact of the accident, and the actual position of the person (i.e. whether they are leaning forwards, or sitting back) can have an effect.